Multiple holder of quartz oscillator plates



Oct. 26, 1948. H. L. BLOXOM EI'AL MULTIPLE HOLDER OF QUA RTZ OSCILLATOR PLATES Filed Sept. 27, 1946 2 Sheets-Sheet 1 HHI Hil I I IHI:

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Oct. 26, 1948. H. L. BLOXOM ETAL MULTIPLE HOLDER OF QUARTZ OSCILLATOR PLATES 2 Sheets-Sheet 2 Filed Sept l INVJI INTOR.

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Patented Oct. 26, 1948 MULTIPLE HOLDER OF QUARTZ OSCILLATOR PLATES Harvey L. Bloxom and Elbert M. Shideler, Council Bluffs, Iowa Application September 27, 1946, Serial No. 699,752

7 Claims. 1

This invention relates to piezo-electric-crystal units, and is herein illustrated as directed to a unit adapted to accommodate a multiplicity of such crystals.

According to general practice, crystals, characterized according to their particular frequencies, have been furnished in electric units, each comprising a single crystal of known frequency mounted in a housing and electrically connected to suitable terminals of such character as to make possible substitutions in an oscillatory electric circuit of one unit for another when it becomes necessary or desirable to alter the frequency characteristic of that circuit.

Units of the above general character may be regarded as relatively complicated when taken into account that one of such units is capable of use in the tuning of an electrical circuit to only one given frequency-to say nothing of the complications that would arise and other undesirable factors, such as excessive Weight and bulk, that would be encountered, were a multiplicity of such units of varying frequency characteristics employed in combination with a multiple switch arrangement in an attempt to solve the problem of selectively placing the crystals in an oscillatory electric circuit according to a given circuit-frequency requirements.

An important object of the present invention is to provide a relatively simple, compact, light and inexpensive multiple crystal unit of such nature that a great number of crystals having respectively different frequency characteristics may be readily and selectively introduced into an electric circuit in order that such circuit may be rendered responsive to a given frequency in accordance with the frequency characteristic of the crystal so introduced.

To the above and other ends the invention contemplates a base equipped with, for example, five prongs by which the unit may be employed in connection with any standard five prong socket, two of which prongs are utilized as contact terminals: a crystal plate holder rotatably mounted on the base and equipped with means for holding a multiplicity of crystals in position to be selectively connected in series with said terminals: and a cover serving as a protective enclosure for the crystals and as a means for facilitating movement of the plate holder to any one of its active positions according to the frequency characteristic of that crystal which the operator wishes to introduce into the oscillatory circuit, it being noted that suitable indicia may be provided on the peripheral margin of the cover in a co-ordinated relation to the respective crystals in order to enable the operator at all times to be advised as to the location of any particular crystal with relation to the contact terminals through which the crystals are adapted to be placed in a circuit.

Other objects and advantages of the invention will become apparent from the following description when taken in connection with the accompanying drawings, in which- Fig. 1 is a plan view of a unit constructed in accordance with this invention, the cover being broken away in order to reveal the crystal plate holding means,

Fig. 2 is an exploded view showing partly in elevation and partly in section the base, plate holder and cover constitutin primary elements of the assembly,

Fig, 3 is a side view of a crystal plate on which are outlined metallic coatings applied to opposite faces of the plate at its respective ends,

Fig. 4 is an edge view of the plate showing the metallic coatings,

Fig. 5 is a face view of a combined washer and detent unit,

Fig. 6 is an edge view of the detent unit.

Fig. 7 is a plan view of the base shown in Figure 2 and illustrating in dotted lines the relation of a crystal plate and its associated contact pins to the spring contacts electrically connected to the contact terminals carried by the base, the peripheral flange of the base being broken away,

Figure 8 is a side elevation of the base as it appears in Figure 7,

Fig. 9 is a bottom view of the base,

Fig. 10 is a bottom view of the assembled unit showing the combined washer and detent unit in its operative position with relation to the base, and

Fig. 11 is a schematic diagram illustrating one of the several crystal plates in closed circuit position with relation to the spring contacts and to their associated contact terminals.

Referring to the drawings, it will be noted that the unit herein illustrated as embodying the pres- 3 ent invention comprises a base [0, a crystal plate holder H and a cover lZ-all of which elements are adapted to be assembled in such relation that the plate holder II and the cover l2 may be rotated in unison with relation to the base 50.

The base l comprises a disc 13, of suitable insulating material, provided with an annular channel l3a, and formed with a central opening l4, which terminates at its lower end in a cuplike cavity I5. It is to be observed that the bottom of the cavity I5 is so formed as to provide an annular row of radially disposed tooth-like lugs l6 which form with each other a series of detent depressions H. The disc l3 carries a group of depending prongs l8, herein shown as five in number, by which the unit may be conveniently accommodated by any standard five prong socket not shown. Of the prongs i8, only those diametrically opposed to each other are employed as circuit terminals although all of the prongs function to firmly retain the base in the socket with which it is adapted to be used. The contact terminals just referred to are connected, respectively, to a pair of sprin contacts and 2| located within the annular channel 13a and through the medium of which a multiplicity of plate crystals, hereinafter more particularly referred to, are adapted to be selectively connected in series with the contact terminals.

The crystal holder i l comprises a disc-like plate 22, of suitable insulating material, having a slightly raised base area 24 and a depending hublike boss 25, the latter being adapted to enter and rotate within the opening M provided in the disc i 3 of the base Ell. In order that the crystal holder l i may be held in proper relation to the base if], the boss 25 is provided centrally with a threaded opening 26 adapted to receive a screw 21, between the head portion of which and the end of the boss 25 is confined a combined washer and detent unit 28. The unit 28 comprises a thin metal disc 30, having a central opening 3! through which the screw 27 passes, the disc being provided with a pair of struck up lugs 32 adapted to enter a pair of openings 34 formed in the lower base of the boss 25, and the lugs being adapted to snugly fit the openings 3 and thus hold the unit 3fl'against turning with relation to the boss 25. It is to be noted that the metal disc 39 is of a diameter substantially greater than that of the boss 25 and that such disc is sheared along an arc somewhat in excess of 180 degrees so as to provide a marginal spring 35 formed intermediate its length with a hump-like detent 36 adapted to ride into and out of the detent depression I? as the plate holder i l is rotated on the base it, the detent 36 in cooperation with the detent depressions l! tending under the action of the spring 35 to retain the plate holder in fixed positions of rotation in relation to the base on which it is mounted.

Passing through and anchored to the plate 22 are a plurality of contact pins 37 and 38 arranged, respectively, in inner and outer groups aboutthe axis of rotation of the plate, the pins of each group corresponding in number to the number of crystal-plate stations afforded by the device embodying the present invention. In this connection it is to be noted, by way of example, that ten such stations are provided in the present embodiment of the invention and that such stations are identified by the numerals 1 to 10 etched or otherwise inscribed on the cover [2. As the plate holder H is rotated, the contact pins 31 are adapted to progressively engage the spring contact 20 as the respective companion contact pins 31 progressively engage the spring contact 2] Referring particularly to Figure 1, it will be noted that each of the contact pins 3'! is connected at its upper end to a spring clip 46 formed from a hat and relatively thin strip of metal bent to a substantially U-shaped configuration and having its free ends turned inwardly one over the other so that the outer faces of the yieldable arms present at their free ends slightly rounded surfaces. Inasmuch as the spring clips .8 are secured, at the juncture of their respective pairs of arms, to the contact pins Bl, it follows that such arms are free to yield unobstructedly toward and away from each other as the crystal plates, herein identified by the numerals l to ID and hereinafter more particularly described, are introduced into and removed from the plate holder 5 l. Referring further to Fig. 1, it will also be noted that each of the contact pins 38 is connected at its upper end to a spring clip ti formed from a flat and relatively thin strip of metal bent to a substantially V-shaped configuration. Since the spring clips M are secured, at the juncture of their respective arms, to the contact pins 38, such arms are free to yield unobstructedly toward and away from each other as the crystal plates i to It are introduced into and removed from the plate holder H. In order to facilitate introduction of the crystal plates i to NJ, the yieldable arms of the respective spring clips ll are turned slightly inwardly so that the outer faces of the arms present slightly rounded outer surfaces at their extreme ends.

As to the crystal plates i to Hi, it may be well to mention that they are of the usual quartz character, and are so finished that their side faces present smooth surfaces which, as shown in Figs. 3 and 4 wherein the plate l is illustrated in detail, are provided with metallic coatings Q2, the coatings on each plate being disposed at opposite ends thereof in a slightl overlapping relation to each other. From the details of construction peculiar to the spring clips 49 and 4! and the details of construction peculiar to the crystal plates I to it, it will become apparent that these plates, which are held in radial positions with respect to the axis of the rotating plate holder H, may be easily introduced into and removed from the plate holder. As shown most clearly in Fig. 1, adjacent pairs of spring clips 35 and ll engage the respective plates and hold them firmly in their operating positions. From an inspection of Fig. 7, it will become apparent that the several crystal plates l to it) may, upon rotation of the plate holder 1 be-progressively placed in an oscillatory circuit by way of the respective pairs of spring clips it] and 4! engaging the respective metal coatings of the respective crystal plates. Inasmuch as the various crystal plates 3 to it) may be arranged according to their individual frequency characteristics, it becomes apparent that the operator, upon rotating the plate holder I, may selectively place in the oscillatory circuit any one of the crystal plates that best satisfies a given frequency requirement. In this connection it will be observed that the crystal-plate-identifying numerals i to it, corresponding to the several crystal' plates, may be utilized in conjunction with a fixed index mark (not shown), to enable the operator to readily determine the correct position to which the plate holder I! is to be rotated in order to introduce a selected crystal plate into the oscillatory circuit, of which the spring contacts 20 and2l together with their associated contact terminals l8 constitute portions.

It will of course be understood that the cover I2 is utilized as a means for facilitating rotation of the plate holder i I, the cover being connected to the holder through the medium of suitable screws 44 passingthrough the disc-like plate 22 of the crystal holder and into the peripheral margin of the cover l2. The cover serves not only as a means for facilitating rotation of the plate holder 'l l but also as a means for protectively housing the crystals i to H1 and their respectively associated elements, it being especially noted in this latter connection that a suitable gasket ring 45 confined between the cover 12 and the disc-like plate 22 of the crystal holder l I may be utilized to effectively guard against the entrance of moisture into the chamber-like compartment 45 within which the crystal plates and their associated elements are confined.

Referring again to the detent unit 28, it is to be observed that this unit is so located on the box 25 of the plate holder II that the hump-like detent 36 bears such a relation to the crystal stations and that the detent depressions H are so located with reference to the contact areas of the spring contacts 20 and 2| as to cause the plate holder when rotated to tend to pause as any two companion contact pins 31 and 38 respectively engage the spring contacts 20 and 2|. By reason of the relationship just described, as existing between the detent 36, the detent depressions I1, the contacts 20 and 2|, the ease with which the plate holder ll may be properly located when selectively introducing any one of the crystal plates l to H1 in the oscillatory circuit is greatly facilitated.

Although it is believed that the operation of the device embodying the present invention may be readily appreciated from the foregoing description, it is desired to emphasize the fact that the device is capable of covering a wide frequence range since it makes posisble the use in a single unit of a multiplicity of crystal plates having different frequence characteristics and enables such plates to be readily and selectively introduced into and removed from an oscillatory A circuit. Should it become necessary or desirable to remove the crystal plates from the device in order to permit substitution of other plates, such removal and substitution may be readily accomplished by removing the retaining screws 44, thereby allowing the cover [2 to be lifted from the plate holder H, thus giving access to the chamber-like compartment in which the plates are confined. Having thus gained access to such compartment, the crystal plates may be radially withdrawn from between the spring clips 40 and 4|, thereby permitting the substitute plates to be introduced by moving them radially inwardly between the spring clips to their respective positions shown in Fig. 1. If for any reason it be-- comes desirable to omit any given crystal plate or any number of such plates, a suitable strip or suitable strips (not shown) of insulating material may be inserted in lieu of the omitted crystal plate or plates, each of such strips of insulating material being of the same, or substantially the same, proportions as any one of the crystal plates adapted for use in connection with the present invention.

Although only one form of the invention is herein shown and described, i will be readily understood that various changes and modifications may be adopted without departing from the spirit of the invention or the scope of the following claims.

We claim:

1. As an article of manufacture, a piezo-electric-crystal unit comprising a base having a pair of terminal contacts, a crystal plate holder rotatable on said base, a plurality of crystal plates radially disposed in said holder and mounted for progressive successive movement into closed circuit position with said contacts upon rotation of said holder.

2. A piezo-electric crystal unit comprising a base having a pair of terminal contacts, a crystal plate holder rotatable on said base, a plurality of crystal plates carried by said holder for pro gressive movement into closed circuit position with said contacts incident to rotation of said holder, a cover within which said plates are housed, said cover being carried by said holder and serving as means to protect said plates and to facilitate rotation of said holder.

3. A piezo-electric crystal unit comprising a movable crystal plate holder, including a plurality of pairs of companion crystal-plate retaining elements; a plurality of crystal plates individually and removably held in operative position between pairs of said companion retaining elements, a pair of circuit terminals, and circuitclosing means operating incident to movement of said holder to establish an electrical connection between said terminals by way of said crystal plates in succession.

4. A piezo-electric crystal unit comprising a base provided with circuit terminals, a crystal plate holder rotatable on said base, a plurality of pairs of companion crystal-plate retaining clips arranged concentrically on said holder, a plurality of crystal plates individually and removably held edgewise between respective pairs of clips, and circuit-closing means operating incident to rotation of said holder to progressively place the clips carrying the crystal plates in electrical connection with said terminals.

5. A piezo-electric crystal unit comprising a base provided with a pair of circuit terminals, a crystal plate holder rotatable on said base and including a plurality of inner and outer pairs of companion crystal-plate retaining clips arranged in spaced relation annularly about the axis of rotation of said holder. a plurality of crystal plates individually and removably held in operative position radially between corresponding pairs of said clips, circuit-closing means operating incident to rotation of said holder to progressively place said crystal plates in electrical connection with said terminals by way of respective pairs of said companion clips, said circuit-closing means including a spring contact connected to each of said circuit terminals and a contact pin connected to each of said clips.

6. A piezo-crystal unit for mounting a plurality of crystals comprising a base having circuit terminals, 2. disc holder rotatable on the base, inner and outer annular rows of pins extending through the base, their ends on the side of the disc adjacent the base being arranged to contact said terminals upon rotation of the holder, and their other ends projecting beyond the other face of the disc, spring plates mounted on the last mentioned ends of the pins of each row having free ends, those springs on the corresponding pins of the two rows forming sets and their free ends cooperating with the adjacent sets :to form yieldable clips, and a plurality of crystal plates mounted in each set of clips.

7. For use in a piezo-electric crystal unit of the type wherein a plurality of crystal plates are car- 7 8 ried and are adapted to be placed successively in an electric circuit, a plurality of pairs of com- REFERENCES CITED panion plate retaining u one clip of each The following references are of record m the pair being of a relatively thin metal strip bent to file Of this p e t: substantia11y a U-shape and the other clip of 5 UNITED STATES PATENTS each pa1r bemg of a relatwely thin metal strip bent to substantially a V-shape, adjacent clips Number Name Date of "said U-shape character being adapted to func- 1,305,871 ower May 28, 1931 tion in cooperation with adjacent clips of said 2,240,450 wolfskiil Apr. 29, 1941 V-shape to retain said crystal plates in their 10 respective operating positions.

HARVEY L. BLOXOM. ELBERT M. SHIDELER. 

